diff --git a/polymorphic/query.py b/polymorphic/query.py
index 454c526..97fc21a 100644
--- a/polymorphic/query.py
+++ b/polymorphic/query.py
@@ -393,6 +393,9 @@ class PolymorphicQuerySet(QuerySet):
                         # now a superclass of real_concrete_class. Thus it's
                         # sufficient to just use the field name.
                         translated_field_name = field.rpartition('___')[-1]
+
+                        # Check if the field does exist.
+                        # Ignore deferred fields that don't exist in this subclass type.
                         try:
                             real_concrete_class._meta.get_field(translated_field_name)
                         except FieldDoesNotExist: